ISO 100, OMD-EM1II and firmware 3.0?

Started 2 months ago | Questions thread
bobn2 Forum Pro • Posts: 61,690
Re: Two pictures are worth a thousand confusions

Chris Noble wrote:

bobn2 wrote:

Chris Noble wrote:

bobn2 wrote:

katastrofa wrote:

My photos look more noisy when I increase the ISO. Why?

Changing the ISO sets the meter so that you choose to use a lower exposure. Lower exposure means less light energy. Less light energy means fewer photons captured in the image. The signal to noise ratio in the image goes as the square root of the number of photons, so if you capture fewer, you get a lower SNR, which you say is 'more noisy'.

You are mixing changes in exposure vs. changes in ISO setting.

With respect, I'm mixing nothing.

Katastrofa's observation is correct even if the exposure does not change (using manual metering for example). The ISO gain introduces additional noise on top of the exposure noise.

That is simply false. It's provably false with suitable examples, which I've posted here several times, but don't have readily available here (if this conversation carries on, I'll post them again, when I can).

Your explanation below that paragraph is full of errors, but rather than explain them to you, I'll take you up on your offer to demonstrate that you are wrong. Post the same exposure, once at ISO 200 and one at ISO 3200. Don't do any noise reduction or sharpening. Adjust the PP brightness to appear the same on the screen. When you look at the shadows, the error of your understanding will be clear.

LOL. I've had many conversations like this, on just this subject, with people, like you, who are pretending to know more than they actually do. The 'what you said is full of errors, but I'm not going to say why' is gambit number one for people who have realised they're out of their depth but haven't got the stones to admit it. As I said earlier, when I have access,to the material, I'll post definitive proof that you're wrong. I'll post what I have. It might not fit your recipe above, but it will be right and quite rigorous. In the meantime, I suggest that you do what you're proposing and post the results. It's clear that you're bluffing, because had you actually done it, you'd know that it doesn't back up what you say at all. BTW, DPR does that test in many of its reviews, and it has never shown higher ISO shots to be noisier than low ISO shots.

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263, look deader.

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